Stethoscope.



K. M. TURNER.

STETHOSCOPE.

APPLICATION FILED SEPT. 10, 1912.

LMKQSZQ Patented July 20, 1915.

lNVENTOR I BY A M Z:- ATTORNEY h l l l'fi KELLEY M, TURNER, FJAllIAIC-A, NEW YORK, ASSIG-NOE TO GENERALACOUSTIC iv OOMPENY, ACGRPORATION OF NEW,

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Specification of Letters Patent. I Patgntgfl July 2o. 1 Q? Applicationfiled September 10, 1512. Serial 1V0. 719,573.

To all whom it may concern: 7

Be it known that I, K LLEY TURNER, citizen of the United States, andresident of Jamaica, in the county of Queens and 5 State of New York,have invented certain new and usefulImprovements in Stethoscopes, ofwhich the -following is a specification.

This invention relates to Stethoscopes.

Hitherto Stethoscopes have been made in various ways, but haveuniversally lacked certain qualities which they could possess to greatadvantage. Foremost among these qualities which the ordinary stethoscopehas lacked is sensitiveness. The heart is like a pump, but itsoperations are on a comparatively small scale, and are furthermore in-Sula-ted from observation by the surrounding tissues, so that only an erof abnormal c delicacy is capable of hearing enough to derive all. theinformation which might derived.

It is the purpose of this invention to so transmit thesounds, or inotherwords, to'

provide such a stethoscope, that a person of normal hearing may getpractically all the information which is capable of being ob tained bythe use of this method of obser-' vation. v v

For this purpose the invention consists in an improved stethoscopemaking use oil a special telephonic transmitter, receiver and ear tubes.I

In the drawings z- Figure 1 is a view showing the parts and generalarrangement of a stethoscope enibodying the principles of thisinvention. Fig. 2 is a face view or the transmitter. Fig. 3 is asectional view of the face of the same.

It will be understood that the heart, in beating, contracts and expands,and in so doing produces two or more sources of sound vibrations, orvibrations analogous to e5 sound vibrations. There is, first, thevibration due to the rush of the blood against 7 d through the operatingwalls, which prouses the usual sound of any rushing liquid,

except to such a slight extent in point of 5c magnitude as to bevirtually inaudible. Be sides this there is the effect of a tap duo thether sudden muscular contraction and Thi a matter of much 'gy than theactual 561 gish or low in pitch to be audible as sound,- or to betransmitted through the air by the phenomenon of radiant or wave energy,as sound is actually. transmitted. In other words, the tap is more inthe nature of those vibrations which are too slow, or in other wordstoofew in number or frequency to be audible to the human ear, or tocarry their energyat all through the air by a wave action. in carryingout the present invention particular care is taken to obtain the fullefiect of both of these sources of sound or energy".

I employ a very sensitive transmitter known as the dictographtransmitter, and familiarly employed in ordinary secretand detectiveservice under this name. A transmitter of this'type is disclosed inpatent to Turner at (47., Ne. 84:4,635. This-patent, however, merelyshows the general 'telephonic features oi? this transun'ster asdisfeatures more particutinguished from its larly related to presentpurpose of use.

1 provide a casing 1 having a compara tively sharp l'lill portion 2which can be pressed against the shin over the heart so as to primarilyinalie an air tight joint around this annular rim. This riin furthermoreso stretches the skin into a kind of membrane or drumhead to ".nation 3,as to render the skin capable of vibratingsomewhat like a drumhead byvirtue of the tap transmitted from the heart; This casing furthermorehas a cavity d which is very shallow and of a form which will closelyfollow the curva ture given to the skin, but without actually touchingthe latter. In this way there is an air pocket formed which iscomparatively large area, but small capacity. ,The result is that slightmovements of the skin result in a comparatively large increase inpressure of the air in the cavityfa-s distinguished from avery sinallincrease of pressure'which would be the case if the cavity were not sosmall in its capacity. It must be borne in mind that these slowmovements or vibrations are not like sound vibrations in the sense thatthey can be carried along by indi-,

stretched condition of the skin and the exif it was theactual pansivearea and small capacity of the air cavity employed, all of whichconditions tend to produce an ultimate movement among the carbon hallsof the transmitter which is about proportionate to the intensity of theheart beat. This is of course the result desired. By it the energy ofthe heart can be plainly heard in its contractions and expansions, andon account of the magnificatioirof sensitiveness the sound is similar tothe sound of heavy pumping machinery in which, on account of the largesize, there is a dull heavy sound by which a trained ear can tell muchabout the operation. The same thing is true of the heart with thisstethoscope. I am aware that the actual sound heard is not really thesound of the heart, but merely a rubbing movement be tween ,very smallcarbon balls which is caused by movements of the heart. But the actualsound received is significant and shows the operations of the heart aswell as sound of the heart. Of course, in addition tothis there is theactual sound of the rushing blood which is trans mitted to some degreeon account of the sensiti'veness of the dictograph transmitter,

The receiver/5 and stethoscope ear pieces 6 and battery 7 present nonovel features. As a part of thestethoscope transmitter, however, I haveprovided a regulating resistance device 8 since it is found in practicethat only certain current strengths give thoroughly satisfactoryresults, so delicate is the operation of this device on account of thegreat difficulty of the work to 0 be performed.

After the instrument has been properly ible of being heard by aplurality of persons simultaneously, through separate receivers andstethoscope ear pieces. Thus, in the clinic where a patient is receivinganoperation', and where it has hitherto been impos sible for all or evenany of the students to use the stethoscope, it is now possible by thepresent invention to have the whole class share in the full benefits ofthe operation throughout. Obviously, this result could not be had by anyprior art devices because the 'patients condition changes, from momentto moment, and even if the students listened by turns at a singlestethoscope, each would get a different result, and each result would bedifierentfrom the one received by the instructor or operating physician.For the use of such. clinics he switch. 8 is particularly desirable,since it permits an adjustment of sensitiveness suitable to the numberof receivers used.

What I claim is 1. A telephonic stethoscope comprising a transmitterhaving in combination with its diaphragm and electrode, a mouth-piecehaving a shallow cavity of relatively large area in the face thereofwhich is adapted to be placed against a portion of the body of thepatient.

' 2. A telephonic stethoscope comprising a transmitter having incombination with its diaphragm and electrode, a mouth-piece consistingof a disk having a shallow saucer shaped cavity of relatively large areain the face thereof adapted to fit against a portion of ,the body of thepatient, and a passage wa leading from said cavity to the diaphragmexposing the latter to the variations of air'pressure in said cavity.

Signed at Jamaica, in the county of Queens and State of New York, this6th day of September, A. D. 1912.

KELLEY M. TURNER.

Witnesses:

EDGAR Lows, E. DOUGLAS 1m GRUcHY.

